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From: Will Deacon <will@kernel.org>
To: "Rémi Denis-Courmont" <remi@remlab.net>
Cc: mark.rutland@arm.com, catalin.marinas@arm.com,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/3] arm64: clean up trampoline vector loads
Date: Tue, 17 Mar 2020 22:30:05 +0000	[thread overview]
Message-ID: <20200317223004.GJ20788@willie-the-truck> (raw)
In-Reply-To: <20200316124046.103844-1-remi@remlab.net>

On Mon, Mar 16, 2020 at 02:40:44PM +0200, Rémi Denis-Courmont wrote:
> From: Rémi Denis-Courmont <remi.denis.courmont@huawei.com>
> 
> This switches from custom instruction patterns to the regular large
> memory model sequence with ADRP and LDR. In doing so, the ADD
> instruction can be eliminated in the SDEI handler, and the code no
> longer assumes that the trampoline vectors and the vectors address both
> start on a page boundary.
> 
> Signed-off-by: Rémi Denis-Courmont <remi.denis.courmont@huawei.com>
> ---
>  arch/arm64/kernel/entry.S | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
> index e5d4e30ee242..24f828739696 100644
> --- a/arch/arm64/kernel/entry.S
> +++ b/arch/arm64/kernel/entry.S
> @@ -805,9 +805,9 @@ alternative_else_nop_endif
>  2:
>  	tramp_map_kernel	x30
>  #ifdef CONFIG_RANDOMIZE_BASE
> -	adr	x30, tramp_vectors + PAGE_SIZE
> +	adrp	x30, tramp_vectors + PAGE_SIZE
>  alternative_insn isb, nop, ARM64_WORKAROUND_QCOM_FALKOR_E1003
> -	ldr	x30, [x30]
> +	ldr	x30, [x30, #:lo12:__entry_tramp_data_start]
>  #else
>  	ldr	x30, =vectors
>  #endif
> @@ -953,9 +953,8 @@ SYM_CODE_START(__sdei_asm_entry_trampoline)
>  1:	str	x4, [x1, #(SDEI_EVENT_INTREGS + S_ORIG_ADDR_LIMIT)]
>  
>  #ifdef CONFIG_RANDOMIZE_BASE
> -	adr	x4, tramp_vectors + PAGE_SIZE
> -	add	x4, x4, #:lo12:__sdei_asm_trampoline_next_handler
> -	ldr	x4, [x4]
> +	adrp	x4, tramp_vectors + PAGE_SIZE
> +	ldr	x4, [x4, #:lo12:__sdei_asm_trampoline_next_handler]
>  #else
>  	ldr	x4, =__sdei_asm_handler
>  #endif

Acked-by: Will Deacon <will@kernel.org>

Will

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  reply	other threads:[~2020-03-17 22:30 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-16 12:40 [PATCH 1/3] arm64: clean up trampoline vector loads Rémi Denis-Courmont
2020-03-17 22:30 ` Will Deacon [this message]
2020-03-18 17:57 ` Catalin Marinas
2020-03-18 18:06   ` Catalin Marinas
2020-03-18 18:29     ` Rémi Denis-Courmont
2020-03-18 19:48       ` Remi Denis-Courmont
  -- strict thread matches above, loose matches on Subject: below --
2020-03-19  9:12 [PATCHv3 0/3] clean up KPTI / SDEI trampoline data alignment Rémi Denis-Courmont
2020-03-19  9:14 ` [PATCH 1/3] arm64: clean up trampoline vector loads Rémi Denis-Courmont
2020-03-23 12:07   ` Mark Rutland
2020-03-23 12:08     ` Rémi Denis-Courmont
2020-03-23 12:14       ` Mark Rutland
2020-03-23 19:04         ` Catalin Marinas
2020-03-23 20:42           ` Rémi Denis-Courmont
2020-03-24 10:37             ` Catalin Marinas
2020-03-24 10:52             ` Mark Rutland
2020-03-24 11:23               ` Catalin Marinas

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